Printing Half Letter size from iPad Air to Epson WF-4830?

I know this is possible because I did it with this exact same printer and ipad in the past, but somehow the settings got wiped between an ipadOS update and a printer firmware update. I can’t remember how I set it up before. I have the paper size set in the printer’s settings, and the paper size in the document I’m trying to print from Pages is also defined to the same parameters, but when I try to print only Letter is available. I know before I was able to print this size directly from Pages and Safari, I did not need any additional app. It simply showed up in the menu.

Printer: Epson WF-4830.

iPad Air 4, all OS and security updates installed.

Can anyone remind me how to get this working?